Fuse switch construction



V. L. WESTBERG FUSE SWITCH CONSTRUCTION July 2,1935.

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Patented July 2, 1935 UNITED STATES `PARENT OFFICE to Benjamin Electric Mfg. Company,

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Plaines, Ill., a corporation of Illinois Application September 21, 1932, Serial No. 634,137

4 Claims.

My invention relates to a fuse switch construction and more specifically to the cartridge fuse type in which a bridging member carried by the box cover controls the circuit between the fuse 5 Contact and the lug contact.

One of the objects of my invention is to provide such a construction in which the bridging member makes direct contact with the fuse clip.

A further object is to provide such a construction in which space is conserved by placing the lug terminal in alignment with the fuse clip.

Another object is to provide such a construction in which the bridge member can be shifted so that the cover can be closed without completing the circuit` Further objects will appear from the description and claims.

In the drawings, in which an embodiment of my invention is shown:

Figure 1 is a .longitudinal section substantially on the line I-I of Fig. 2;

Fig. 2 is an elevational view with the cover and bridging member removed;

Fig. 3 is a perspective View of the cover for the lug contact or bus connection;

Fig. 4 is an elevational View showing the slidable mounting for the bridging members;

Fig. 5 is a section on the line 5-5 of Fig. 2, showing the cover member partly open; and

Fig. 6 is a transverse section through the fuse clip contacts. y

Referring to the drawings in detail, the construction shown comprises a rectangular sheet metal box I, a cover 2 therefor hinged.,thereto at3, an insulating base 4 secured against the bottom of the box, a plurality of cartridge fuse clips 5 mounted on this insulating base 4, terminal lugs 6 for the feed wires 1, a pair of spring contacts 8 for each of the lugs 6, and a bridging member 9 slidably mounted on the hinged cover 2 carrying bridging pieces I0 for completing a circuit between the fuse clips 5 and the lug contacts 8 when the cover is Closed.

Each clip 5 may be secured in place by means of a number of screws extending through the base 4 and threaded into a clamping plate bearing on the clip.

Against the inside of the cover 2 of the box I are secured two angles II, which run vertically in the box, and whose projecting anges I2 form a track along which the bridging member 9 slides. The frame of the bridging member 9 1s composed of four angles |3, I3 and I4, I4, welded together into a rectangular frame as shown.

Flanges I5 of the angles I3 embrace and slide along the outer surfaces of the track flanges I2. Four screws I6 and I'I are threaded through flanges I5 and bear in slots I8 in the track flanges I2, serving both to prevent the bridging member 9 from falling away from the track 5 anges I2 and also to limit, by their arrival at the ends of their respective slots I8, the motion of the bridging member 9 with respect to the cover 2. The two extremes of the motion of the bridging member 9 are shown in dotted line and in full line in Fig. 5.

The bridging member 9 is snapped in either of these two extreme positions by the action of the leaf-spring I9 secured at 20 to the cover 2 and pressing away from the cover upon the screw I'I, 15 which screw II, for this purpose, is made longer than the other retaining screws I6. The leaf spring I9 has two portions 20a inclined with respect to the direction of its pressure. When the bridging member 9 is in either of its extreme 20 positions, a corresponding one of these inclined portions 20a `acts to force the screw II against the end of the slot I8, thus retaining the bridging member in that extreme position. The strength of the spring I9 and the inclination of 25 the portions 20a are such that, while the bridging member 9 will be lretained in either extreme position, an operator can easily force the bridging member out of either snapped extreme position in order to slide it to the other extreme 30 position.

Within the cradle formed by the four frame angles I3 and I4 are held insulating blocks 2|, to the bottom of each of which is secured a bridging piece I0. Each bridging piece is composed of two members 22 and 25. The U-shaped spring Contact member 22 of the bridging piece I0 is secured to the insulating block 2| by means of a screw 23, which passes down through the insulating block 2| and through the spring contact member 22 and threads into the securing portion 24 of the bridging piece member 25. When the cover 2 is closed, the spring contact member 22y grasps the fuse clips 5, making electrical contact therewith. Bridging piece member 25 is rigid and has two portions,-a securing portion 24 into which thread screws 23, which secure portions 24 and the spring contact member 22 to the insulating block, and which press the two bridging piece 50 members 22 and 25 into mutual electrical contact, and a knife contact portion 2E which engages the spring contacts 8 when the cover 2 is closed and the bridging member 9 is in the position with respect thereto shown in full line in Fig. 55

5. If the bridging member 9 is in the dotted-line position of Fig. 5, the knife contact portion 26 does not engage the spring contacts when the cover 2 is closed.

Each pair of spring contacts 8 and its terminal lug E are secured t'o eachother and to the insulating base li by means of a screw 2l and a nut 28 and are placed in line with their corresponding fuse clip 5. The cooperating contacts 5, between which the knife contact portion 26 enters, are held in proper position relative to each other by means of a down-turned flange 28a on one of the contacts engaging the edge of the base of the other contact. Protecting each terminal lug 6 and its pair of spring contacts 8 is an insulating housing 29 provided with a slot 30 for the admission of the knife contact 26 and with a hole 3E for the admission of the feed wire l.`

These housings are secured to the insulating base 3 by means of screw clips 32 bearing upon ears 33 with which the housings are formed. These housings keep the operator from touching the ter-- minal lugs 6 and the spring contacts 8, which, being connected tothe feed wires l, are at all times live. The fact that an individual bridging unit 9 is provided for each set of contacts 8 and the fact that each bridging unit is mounted in such a manneras to provide a limited floating action, insures a good contact on all the contacting surfaces for each set of contacts.

When the cover 2 is closed and the bridging member 9 is in the position, with respect to the cover, shown in full line in Fig. 5, spring contacts 8 will grasp the knife contact 26 and the spring contacts 22 will grasp the fuse clip 5. In

this way there is formed an electrical circuit from the feed wires 1, through the terminal lugs 6, the spring contacts 8, the knife contact portion 26, the securing portion 24 of the bridging piece member 25, and the\U -shaped spring contact member 22 to the fuse clip 5. If the box l is opened, however, for inspection or replacement of fuses, the bridging member 9 will move back with the cover, carrying with it the knife contact 26 and the spring contact 22 and withdrawing them respectively from engagement with the spring contacts 8 and the fuse clip 5. This breaks the circuit from the feed wires 1 to the fuse clip 5, and electrically isolates all exposed parts of the circuit from the feed wires. The parts of the circuit that are still live, the spring contacts 8 and the terminal lug 6, are covered by the insulating housing 29. It is thus impossiblej'or the operator to come in contact with any live conductor while changing fuses. If the bridging member is left in the full-line position of Fig. 5, the door, 1n closing, will reestablish the circuit from the feed wires I to the fuse clip 5 by carrying the knife contact member 26 and the spring contactmember 22 back into engagement respectively with the spring contacts 8 and the fuse clip 5.

If it is desired to close the door 2 without reestablishing the circuit from feed wire 1 to'fuse clip 5, the bridging member 9 will be shifted to the dotted-line position of Fig. 5, in which case the knife contact member, in rotating with the Having thus described my invention, what I aocaeii claim and desire to secure by Letters Patent is:

l. A fuse box construction comprising a box, a cover therefor, spaced fuse clips mounted in the box for engaging the end contacts on a cartridge fuse, a contact for a wiring terminal also mounted in said box in substantial alignment with the cartridge fuse contacts, and a bridging member for bridging between the wiring terminal contact and one of the fuse contacts, slidably mounted on the cover to move longitudinally with respect to the cartridge fuse from a position in which the bridging member does not close the circuit between the wiring terminal and fuse when the cover is closed to a position in which it does close the circuit between the wiring terminal and fuse when the cover is closed.

2. A fuse box'construction comprising a box, a cover therefor, spaced fuse clips mounted in the box for engaging the end contacts on a cartridge fuse, a contact for a Wiring terminal also mounted in said box in substantial alignment with the cartridge fuse contacts, and a bridging member for bridging between the wiring terminal contact and one of the fuse contacts, slidably mounted on the cover to move longitudinally vwith respect to the cartridge fuse from a position in which the bridging member does not close the circuit between the wiring terminal and fuse when the cover is closed to a position in which it does close the circuit between the wiring terminal and fuse when the cover is closed, a contact portion of said bridging member lying substantially opposite a contact on the fuse when in circuit-closing position.

3. A fuse box construction comprising a box, a cover therefor, spaced fuse clips mounted in the box for engaging the end contacts on a cartridge fuse, a contact for a wiring terminal also mounted in said box in substantial alignment with the cartridge fuse contacts, and a bridging member for bridging between the wiring terminal contact and one of the fuse contacts, slidably mounted on the cover to move longitudinally with respect to the cartridge fuse from a position in which the bridging member does not close the circuit between the wiring terminal and fuse when the cover is closed to a position in which it does close the circuit between the wiring terminal and fuse when the cover is closed, said fuse-engaging contact having contact portions embracing a contact on the fuse and said bridging member comprising a contact member which straddles a contact on the fuse when in circuit-closing position.

4. A fuse box construction comprising a box, a cover therefor, spaced fuse clips mounted in the box for engaging the end contacts on a cartridge fuse, a contact for a wiring terminal also mounted in said box in substantial alignment with the cartridge fuse contacts, and a bridging member for bridging between the wiring terminal contact and one of the fuse contacts, slidably mounted on the cover .to move longitudinally with respect to the cartridge fuse from a position in which the bridging member does not close the circuit between the wiring terminal and fuse when the cover is closed to a position in which it does close the circuit between the wiringterminal and fuse when the cover is closed, said bridging member comprising a contact blade for engaging the wiring terminal contact, and an insulating housing for said wiring terminal contact having an opening through which said blade enters for engagement with the wiring terminal contact.

lvIvIliN LUTHER WEs'TBERG. 

